Stoker



Aug. 7, 1951 G. N. MILLER 2,563,688

STOKER Filed June 5, 1947 2 Sheets-Sheet l I "Ill/1,4 1,.

IN V EN TOR.

2 GEORGE/V. M/u. E/e

Attorney g 7, 195] G. N. MILLER 2,563,688

STOKER Filed June 3, 1947 2 Sheets-Sheet 2 INVEN TOR. GEORGE /Y M/LL Eig Patented Aug. 7, 1951 UNITED STATES PATENT OFFICE STOKER George N. Miller, Castalia, Ohio Application June 3, 1947, Serial No. 752,025

4 Claims. (01. 110-103) This invention relates to stokers, and more particularly to an automatic stoker for coaliired boilers.

An important object of the present invention is to provide a novel form of stoking means for boilers wherein powdered or other relatively finely divided coal is fed to the fire bed of a furnace and evenly distributed thereover.

A further object is to provide such a stoker having novel means operative in conjunction with the coal feeding means for blowing the coal into the furnace to evenly distribute it over the fire bed.

A further object is to provide a stoker wherein a reciprocating pusher device is operative for moving coal in measured amounts per minute into a furnace and to blow the coal thus fed to the furnace over the fire bed in a uniform distribution of the coal.

A further object is to provide automatic stoking means of the character just referred to wherein the coal feeding and distributing devices are automatically simultaneously operative.

A further object is to provide a coal distributing jet blower mechanism for a stoker wherein the jet devices employed are capable of relative adjustment so as to uniformly blow the coal over the fire bed to provide a uniform distribution of the coal even for deep furnaces havingrelatively long grates and fire beds.

A further object is to provide a novel coal feeding mechanism in the form of a reciprocating pusher operative over a wear plate which is detachable and replaceable with a new plate .after substantial wear has taken place.

A further object is to provide novel means operative independently of the automatic parts of the apparatus for determining the rate of feeding the coal to the furnace.

Other objects and advantages of the invention will become apparent during the following description.

In the drawings I have shown one embodiment of the invention. In this showing Figure 1 is a vertical sectional View through the stoker and adjacent parts of a furnace, parts being shown in elevation and parts being broken away.

Figure 2 is a horizontal sectional view on line 2-2 of Figure 1, parts being broken away.

Figure 3 is a plan view of the stoker mechanismper se, portions of the furnace wall and the stoker feed tube being shown in section and parts being broken away.

Figure '4; is an inside face view of a portion 2 of the front furnace wall showing portions of the stoker apparatus.

Figure 5 is a detail perspective view of the pusher feed element, and

Figure 6 is a detail perspective view of one of the pusher guard plates.

Referring particularly to Figure 1, the numeral I0 designates a boiler furnace as a whole having a front wall H, the boiler proper being indicated by the numeral l2. The usual grate structure [3 is arranged in the furnace and divides the space beneath the boiler into a fire box It and ash pit [5.

The wall I I is provided with a suitably shaped opening [8 in the bottom of which is arranged a relatively heavy base plate l9 cored out in its bottom as at 20 and having its inner edge projecting through the opening l8 approximately to a point flush with the inner surface of the wall II. The base plate I9 forms the main supporting structure for the apparatus, as will become apparent, and this plate projects a substantial distance outwardly from the furnace wall II and is suitably supported at its outer end by means of a post or similar support 2|.

The inner portion of the base plate 19 forms part of a tunnel-like structure defining a coal inlet tube, such tube further comprising side plates 25 and a top plate 26 preferably engaging the upper edges of the side plates 25 by a tongue and groove arrangement 21. The lower edge portions of the side plates 25 may extend downwardly along the outer edges of the base plate [9, as shown in Figure 4.

The outer end of the top plate 26 terminates approximately at the point 28 (Figure 1) and outwardly of such point is arranged a hopper spout 29 supporting an upper sheet metal hopper 30. The spout 29 may have its side walls 29 integral with or separate from the side walls 25, and the front and rear walls 3| of the hopper spout may be formed in any desired manner, that is, either integral with the side walls 29' or sep aratetherefrom, etc. The outer and inner walls 3! have their lower edges terminating approximately at the points 32, thus providing openings straight through the feeding tube. The opening defined by the opening 32 remote from the furnace wall is normally closed by a gate 34 having a hand piece 35 at its upper end to facilitate the raising and lowering of the gate, when desired. The hand piece 35 turns outwardly and in the angle between such hand piece and the gate 30 is arranged a bolt 36 passing through ears 3'! carried by the side plates 29'. The bolt 36 clamps A control gate 40 extends between the sidel'lf" plates 25 adjacent the inner wall 3| of the hop H per tube. The adjacent edges of the walls 36 are provided with ears 4| connected by a. bolt 42-410 clamp such edges of the side platestoward each other and into engagement withth'e' edges of the gate 49. Thus the gate 40 may be clamped; in adjusted positions with its lower edge at the desired; elevation to predetermine the rate; of feeding of the 'coal to the furnac'einfa manner to be les r da e up e i d f he ei i' i with a hand piece 43 to facilitate moving the gate 42 to vertically adjusted positions 'while the bolt &2 is loosened. V

cheate e ee. i hermal? .i ei e with the gate illl an open ing l i through which access can be. had tothe interior of the feeding tube. Th eni s ad s girlie h fire x w pert' cemb s enend h areae n n is d ble ..sa e- 5. lide le ei i es 5 a ried by the side plates 25 Coal fed downwardly from thehopper into the f t b defined by 'thaplates zcfandze is adapted; to be moved. into. the furnace by a pus e 9 1 denim-Pe spe t v l ie r 5 of he iw i as-v h iiiu he e rab y a single e ins avihs ehr s al We 5' d a dnes de n es-5 1 hen h r isicored 1 i t t u e s de. s, .3,; m r vidi epend n fla e -fiii; hro ielic i li ed fihe u he t o wa d r ne aii d ei i e i h r in fiat, as shownin ures, land 5. At its outer end, the pusher. is oyided. with anupstanding flan ate a t, er j i e el des r d.

The pusher, may operate 1 directly over the 1 top ably is arranged ;over. tne.base' plate;1'9 and prejects outwardly beyondthepusherto be secured byscrews orfthe lihe J61 "(Fi:gure 13;) to the base platelS As .the pla fitl'becoines badlyworn, the screws Bl may be removed. and. anew. plate i l di ie eni L 9 ie ei' eii e esi l i ie flat plate which can ibe .r ively cheaplynnanufacm d: h islnermi ine. g o ic plee m ii of uch memben ei rd 'iaes;

ployed one oi these members 1, being. shown in perspective in Figure 645f the drawings. Each of h e P a s qmii isee alimflerise ie e u as at "6] to receive screws or the like not shown) for attaching the guard platesto the adjacent side plates 25 Eachguard plate further com-V prises an. inwardly extending shoulder G8 terminating in a dowhwardl yfextending flange 1 E9 overhanging. the adjacent flanges 52 of the pusher 50.

motor s. m lq i ii; er ee pr e iin h pusher 58. In the present instance, such motor connected as at 88 to one end of a link 8|.

7 Each of the pipesllfiand sigextends t is shown in the form of a small conventional steam engine 12 having a steam chest 13 controlling the operation of the piston (not shown) of the engine. Such piston has a conventional piston rod 14 provided with a coupling 15 com prising a pair of discs engageable against opposite sides of the flange 51 to transmit reciprocating motion to the pusher.

In practice, a conventional" mechanical lubricator 18 is preferably connected toi the-motor or engine 12 and is operable by a rocking crank 19 The opposite end of this link is connected by a pin 82 to the pusher 50, the latter being provided with anopening- 83 (Figure 5) for connection of the P RQZIIlQTQPQ- Steam for operating' the engine 12 is tapped fro nth'e boiler l2 through a pipe 85 (Figure 1). This pipe leads to a conventional ofi-and-on regulator. 86 having a. weighted arrnSBf todetermine its-operating pressure, Themegulator-fldis of such type thatit opens upon a drop'inpres sure in theboiler IE to permit the flowi'oi. steam through the pipe85, and cuts oifthe fiow of such steam when the boiler pressure rises above such predetermined pressure,

From the regulator" 86 a supply pipes]. ex; tends downwardly and isprovidedwith a suitable fitting 88leadingtoa pipe fiflnconnectedto the steam chest 13 and a valve .90, acti igjas a thro t tle valve for the. engine. l2, isvarranged in; the pipe 89. The fitting 88 is also suitably connected by a pipe el toj asteam manifold (Figuraz),

'for a purposto be described. It; willbefa'ppar ent that theengine. 72 ,operates. when steam is supplied through pipe v 37, to efiect reciprocation of the enginefpiston and thus. reciprocate the pusher 50.

Beneath and parallelto thebase plate, I9 is arranged a plurality-0f pipes for supplying steam to the firebox to distribute coalfed to the fur.- nace bythepusher 5,0. In the presept instance, these p'ipes have been shown as beingfour in number, the outer two pipes being indicated by the numeral 96and the inner. twdpipesbeing indicated by the numeral 91. Each offthese four pipes is provided with a; manually. controlled valve 98,;an'd the pipes 9 6 are directly tapped into theste'ammanifold 93. z 1

For. each oi the pipes 91 there is prov-ideda sleeve flelthrough which such 1bipe,extends, each sleeves!) beingprovidedfwitha su able packing gland H30. Thisarrangernent is .p 1 dedin o;- d'er that the two, 'pipes 9l .'may. 'ax'ially adjusted, for a purpose to be} described 'and it will be pp re t h teach pipe-g xtefi s ntqim manifold 93 to be supplied with stearntheretroni. ro iehmetal sleeve I93 built into ,the .fur ace, wallfl'l, and the inner endsof each ofthe four pipes terminat'es' in a nozzle I04. Separate noz'zlsfmay be connected to the pipes 55 and 91, butin practice I have found it fully practicable merelyto flatten the endsof, the pipes flfi and 91'; as lshown in F s an wh b el'iiiozzle.j srr r vided with a narrow elongated discharge orifice (Figure 4); In order to provide for even dis;- tributionoi the fuel laterally of the grate as well as n nal her n: h iezzle I 0 r curved outwardly from the center line of, the furnace, as shown inFiguresQand 3.1 7' V The ipe 6 M 11 re, r fer b yrr secli a common horizontal plane. Ju .;beneath.. such .nieeei e w teie eei iiei iii {is rran a distributing plate I08 preferably in'the form of a bracket having a depending flange I09 secured to the furnace wall I I. The top I I of the ditributing plate forms the operating surface thereof and is preferably semi-circular in shape, as shown in ure 2.

Operation Assuming that the furnace is in operation and the steam pressure in the boiler is above the predetermined point referred to, none of the parts of the present apparatus will be in operation. As soon as such pressure drops below the predetermined point referred to, the regulator 86 will admit steam from the boiler I2 through pipe 85 and through pipe 81 to be distributed to the engine I2 and manifold 93 through the various connections thereto. The engine 12 will then start to operate to slowly reciprocate the pusher 50, the speed of operation of the engine I2 being controlled by the throttle valve 90. Goal will be fed into the horizontal feed tube and on to the pusher 50, and. each inward movement of such pusher carries coal towardthe fire box and permits the dropping of more coal on the outer portion of the pusher. At each outward movement of the pusher 50, that is, movement toward the engine I2, the gate 34 prevents any retractive movement of the coal and accordingly the pusher will slide beneath the coal thereon. Each inward movement of the pusher therefore will result in the feeding of coal into the fire box to be dropped to the distributing plate I08.

During the continuation of such operation, steam will be supplied to the manifold 93 and will flow from such manifold in constant streams through the pipes 96 and 91 to be discharged from the nozzles I04 thereof. These nozzles having elongated relatively fiat orifices, the steam jets will spread in a fan-like fashion and will blow the finely divided coal from the top surface I ID of the distributing plate. Thus the coal will be blown into the furnace and fanned out over the bed of coals. The coal will be fed to the greatest extent toward the center of the top surface I I0, that is, in the region on the nozzles I04 of the pipes 91. These pipes, therefore, affect the greater percentage of the coal and the necessary quantities of coal will be blown by the center nozzles toward the back or remote end of the fire box. To properly distribute the coal throughout the length of the fire box, the pipes 91 are axially adjustable to blow the proper percentage of coal rearwardly' into the furnace. Such axial adjustment of the pipes 91 adjusts the position of the nozzles I04 of such pipes, one adjusted position of each of such nozzles being shown in dotted lines in Figure 2. All of the pipes 96 and 91 may be made adjustable, but in practice I have found that it is unnecessary to adjust the outer pipes 96, the proper adjustment of the pipes 91 and their associated nozzles taking care of the requirements of furnaces of any depth. The longitudinal adjustment of the nozzles I04 assures the even distribution of fuel over the grate from front to back, while the curvature of the nozzles away from the center line of the furnace assures proper lateral distribution of the coal.

As soon as the boiler pressure has been brought up to the proper predetermined point, the regulator 86 will cut off the supply of steam to the engine I2 and to the distributing nozzles I04, and accordingly the apparatus becomes inoperative. The operation is automatically resumed whenever the boiler pressure drops below the predetermined point referred to.

The apparatus is relatively simple in construction and all parts arev readily accessible for replacement and repair. .For example, the bolt 36 may be loosened and the gate 34 elevated if it becomes necessary to dislodge impacted lumps of coal within the feed tube, or if it becomes necessary to gain access to the interior of such tube for any other purpose. The wear caused by reciprocation of the pusher 50 takes place on the plate 60, and as previously stated, such wear plate is removable by taking out the two screws 6| (Figure 3).

The feed tube defined by the elements 25, 26 and I9 may be formed integral but it is more practicable to form them as shown in Figure 4 because of ease and economy in manufacture, and ease of assembly and replacement if the latter becomes necessary. The upper edges of the plates 25 are maintained properly spaced by the tongue and groove arrangement 21, and the lower ends of the plates 25 are held in position by the lateral extremities of the base plate I9. It is not otherwise necessary to secure the elements in position, and quite obviously these elements may be cheaply manufactured and easily assembled.

The guard plates 65 serve to prevent coal from overflowing the edges of the pusher 501 and becoming lodged adjacent the lateral edges of or beneath the pusher, thus maintaining the latter in proper operating condition.

The gate 49 and the proper operation of the throttle valve 9!} determine the rate at which coal is fed to the furnace. The throttle controls the speed of operation of the engine I2, while the gate 40 controls the depth of the body of coal being moved toward the fire box by the pusher. Thus coal may be supplied at any desired rate to the furnace. The distribution of the coal thus fed to the furnace is controlled by axial adjustment of the pipes 91 and by the proper controlling of the valves 98 to supply steam at the desired rate to the nozzles I04. Through proper adjustment to thevarious parts referred to, coal may be supplied at the desired rate to the furnace for most efficient operation, and the coal may be perfectly distributed over the fire bed. Having properly adjusted all of the parts referred to, the apparatus thereafter is fully automatic in operation without any attenion.

The usual draft means (not shown) for the furnace is controlled in any conventional manner, and the opening 44 (Figure 1) provides for the admission of secondary air to the fire box I4 to properly support and complete the combustion of the fuel.

I claim:

1. A furnace having a fire box and a grate therein, and a front wall provided with a horizontal opening above the level of the: grate, a coal supply tube communicating with the fire box through the opening in said front wall, a hopper outwardly of said wall, a hopper tube communieating between said hopper and said coal supply tube for supplyin relatively finely divided coal to the latter, said hopper tube having one vertical wall nearest the wall of the furnace arranged for vertical movement to predetermine the depth of the coal in said supply tube, a horizontal pusher horizontally reciprocable in said supply tube to move coal into the fire box at each inward reciprocation of such pusher, a motor for reciprocating said pusher, said pusher having upstanding flanges along its longitudinal edges, and stationary flanges carried by the sides of said coal supply tube and projecting downwardly over the upper. edge'sof. the: flangesgbisaida pusher to minimizethe dropping of coal; over, the; edgesazof said pusher.

2; A steamboiler havin a boiler unit; a fire box; a grate, andairont; wall provided. with-a horizontal. opening therethroughzabove the; grate;

- a coal supply tube communicatingwith the fire box. through. the; opening in saidiwall. and. pro: jeeting outwardly therefrom; a hopper; a; vertical hopper tube. for-supplying: relatively fine-151* die vided coal from said hopper to said supply tube,.a horizontallyreciprocablepusherv in said. supply tubeoperable: upon each. inward reciprocation thereof for supplyingcoalzto. saidfireboxiavsteam engine for reciprocating. said; pushem. a; dis: tributing. plate-carried by said front: wall; ofgthe furnace. and projectinginwardlyztherefrom above the; grate. and below the: opening through: such wall and onto which coalzialls from said, supply tube. aplurality' of. fluid pressure.tubes;=proiect= inghorizontally throughjhe front wall anditer+ minating. in discharge; nozzles-oven said; distributing plate, meansoperable upona predetere mined drop inpressure insaidaboilen unit for supplying steam {to said engine and to said .Iflllid pressure tubes, and,v means .-,for-controlling said engine independently of.5 13118-2 supply: of:v steam: to saidfiuid pressure tubes, 7

3. A steam boiler having a boiler. unit,, a f1re 'b0X,, a grate. andia front. wall provided, with a horizontal. opening therethrough above the grate, a: coal supply tube; communicating with the firebox through theopening in said wall and projecting outwardly therefromya hopper, avertical hopper tube; for supplying relatively finely dividedcoal from said hopper to saidsupply tube, a,v horizontally reciprocablespusher. in. said supply tube, operable, upon each inward. reciprocation thereof .for. supplying coal to saidzfire .boxpazsteam engine for. reciprocating said; pusher, a. dis.- i

tributing plate; carried by said: front wall of. the furnace andprojecting-inwardly therefrom above the grate, and below thebpening throughssuch wall and onto; w-hichpcoal fallsifrom said-supply tube, a pluralityof vfluid-pressure tubes projecting horizontally through-thefrontwall and terminating .in dischargesnozzles .over saididistributing platea manifold communicating;withasaid fluid pressure tubes, means operable upon a predeter; mined. drop.- in; pressure;imsaidrboiler' unit. for hp rines am q saidreneine andto said imam;- fold and. means for oontrolling'said engine inde-q pendently ofvthesupply of steamto said manifold; 5 l.

4*. A; furnace. having-i afirebox and a grate therein-,. and, a frontwall provided with-ahori zontal opening above the level of the gratefi a'co'al supply tube communicating. with the fire box through said horizontal opening, means for supplying coal't'o said tube, a pusher horizontally"reciprocablel said supply tubeto' moVecoaFiiitb thefire box at each inward reciprocation of said pusher, an engine for reciprocating said pusher; a distributing plate projecting into the" fire" box from" said front wallabove thelevel offlthe'g'rat'e; a fluid pressure tube projecting throughsai'd furnace wall" and terminating in a: disoharge'no'z; zle' arranged over'said distributing plate, aisburee oi pressure" fluid supply, a conduit'co'nneet'ing sai'dsoure'e to said fluid pressure tube, means in said conduit for" con'trollingi' the supply of pres sure flui'd' therethrough, a pipe connecting said engine to said conduit between said control means therein and said fluid pressure" tube): and means inisaid pipefor' controlling thesp'eed' of operationof said engine.

. GEORGE Manors.

REFERENCES CITED UNITED STATES PATENTS 

